(57) In transmission systems of the point-multipoint type (PMP) a master station and one
or more terminal stations are defined; a downstream channel from the master station
towards the terminal stations and an upstream channel from the terminal stations to
the master station are also defined.
The system can be optimised in different ways for different applications. An example
can be the fixed packet or variable packet optimisation; another example can be the
optimisation for the operational flexibility or for the efficiency.
These optimisations give origin to different systems and different standards, incompatible
among them, with different frame structures.
The present invention solves the problem of implementing a multi-standard terminal,
that is, terminal capable to automatically adjust to any frame structure in a limited
set of different structures, optimised in a different way.
The master station, which results of course being specialized to operate in accordance
with a specific operation method, imposes said operation method and the terminal stations
slaved to the same, conform to them, recognizing the operation mode from the frame
preamble.
The frame preamble, periodically transmitted from the master station to the terminal
stations, according to the present invention is differentiated in different sequences,
each one identifying a different operation mode.
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